"a creeping motion," 1818, from creep (v.). Meaning "despicable person" is 1935, American English slang, perhaps from earlier sense of "sneak thief" (1914). Creeper "a gilded rascal" is recorded from c.1600, and the word also was used of certain classes of thieves, especially those who robbed customers in brothels. The creeps "a feeling of dread or revulsion" first attested 1849, in Dickens.

creep

noun

A disgusting and obnoxious person; crud, jerk, nerd •An isolated 1886 use seems to refer specifically to a cringing sycophant rather than a generally repulsive person: The man is nothing but a creep/ poets loyal to Blake and Whitman, the ''holy creeps''/ How to spend our money on making some creepo more creative in the growing world of weirdness